1. Field of the Invention
The present invention relates in general to a method for assemling a wheel assembly (viz., tire-mounted wheel), and more particularly to a method for coupling a tubed tire with a wheel.
2. Description of the Prior Art
Among tires for vehicles, there are tires of a tubed type which comprises a discrete external covering of rubber (which will be referred to as a tire proper in the following) and an inflated tube coaxially disposed in the tire proper. The tube has at its radially inner side an inflating valve which projects inwardly and then axially outwardly therefrom. Upon practical use, the tubed tire is tightly mounted on a rim of a wheel having the inflating valve passed through a valve aperture formed in the rim. With this coupling process, a so-called tired wheel is provided.
In order to achieve a balanced rotation of the tired wheel thus assembled, respective dynamical natures, viz., uniformities, of the tubed tire and the wheel are checked before coupling of the tubed tire and the wheel. That is, the coupling therebetween is so made that the respective dynamical natures of them are cancelled from each other. Usually, with an aid of a uniformity tester, the radial force variation (RFV) of the tubed tire (viz., the variation of force applied in a radial direction of the tire) and the radial run-out (RR) of the wheel (viz., the radial vibration of the wheel rim) are measured to find out their maximum and minimum value points and put marks on these points on the tubed tire and the wheel rim. The coupling is then carried out in a manner to match the position of the mark representative of the maximum value point on the tubed tire with the position of the mark representative of the minimum value point on the wheel rim, or vice versa.
However, hitherto, the proper or matched coupling of the tubed tire and the wheel has been very difficult or at least troublesome because of the following reasons.
As is seen FIG. 4, during the coupling step, the inflating valve 3 of the tube 2 is put through a valve aperture 5 of the wheel rim 4. Upon this, the relative positioning between the tube 2 in the tire 1 and the wheel rim 4 is unconditionally decided. That is, coaxial displacement of the tube 2 relative to the wheel rim 4 is no longer permitted. Thus, for matching the position of the maximum or minimum value mark 6 on the tire 1 with the position of the minimum or maximum value mark 7 on the wheel rim 4, it is necessary to slide the tire 1 relative to the tube 2. However, this sliding of the tire 1 requires a great force due to a considerable friction generated between the tire 1 and the inflated tube 2.
One measure for solving this drawback is to form the valve aperture 5 after the matched coupling of them. However, this measure can not be used in wheels 8 and 9 of a deeper rim type and a side ring rim type as illustrated in FIGS. 5 and 6 respectively. In the deeper rim type wheel, the valve apeture 5 is formed in a side wall 4b of an groove 4a of the rim 4, and in the side ring rim type wheel, the valve aperture 5 is formed in a center of a bottom 4c of the rim 4. However, neither of them can prepare a working space for receving or setting therein punching tools, such as a die 10 and a punch 11 as shown in FIG. 7. That is, in the wheel 8 of FIG. 5, the size of a space S.sub.1 defined between the rim 4 and a swelled portion of a disc 12 is insufficient for setting therein the die 10 or the punch 11, and also in the wheel 9 of FIG. 6, the side of a space S.sub.2 defined between the rim 4 and a depressed portion 12a of the disc 12 is too small.
FIG. 8 shows another side ring rim type wheel 9a in which the disc 12 is secured to a side edge portion of the rim 4. Because no obstruction is present around the bottom 4c of the rim 4, formation of the valve aperture 5 in the rim bottom 4c is readily effected. However, in this wheel 9a, it becomes necessary to provide the disc 12 with another aperture 12b through which the inflating valve 3 is projected into the open side of the wheel 9a. Of course, the formation of such another aperture is troublesome.